P155 Interobserver variability in cause of death in a lung cancer screening trial: a pilot method study
Bibliographic record
Abstract
Background A reliable process to determine cause of death (CoD) is important in the context of lung cancer screening trials to differentiate between all-cause and lung cancer related mortality. Previous lung cancer screening trials have used independent expert reviewers to report a consensus. Here, we adapt this method for a large lung cancer screening trial and report the interobserver agreement for CoD, and the agreement with death certificates. Methods Patients diagnosed with cancer following baseline at lung cancer screen in the SUMMIT study (NCT03934866) who had died were selected sequentially. Two observers (respiratory registrars with minimum 4 years specialty training) independently conducted review of available clinical notes, including pathology reports, radiology reports, and blood results to determine lung cancer related CoD. Deaths were classed as ‘Definitely’, ‘Probable’, ‘Possible’, ‘Unlikely’, ‘Definitely Not’, and ‘Contributory to other CoD’ (adapted from1). After consensus review, the final rating was compared to medical certificates of cause of death, where CoD was classed as lung cancer related if lung cancer was listed in 1(a), 1(b) or 1(c). Results Thirty-nine patients were included, who had a mean age of 69 and were 51% male. Most cancers were stage 1 at diagnosis (51%), with the next most common being stage 3 (31%). Overall agreement between reviewers was moderate (table 1). When ‘definitely’ and ‘probable’ were combined as lung cancer related deaths, and all other categories as non-lung cancer related death, agreement was excellent (κ=0.84). At review, 5/39 cases had disagreement between observers and were resolved by consensus. Agreement between reviewers and the death certificates was moderate (κ=0.54). The methods had agreement in 19/39 cases, and an equal number of lung cancer related deaths (23/39). Conclusion Independent blinded review to determine cause of death has excellent interobserver agreement. Robust definitions of lung cancer related mortality are important for trial endpoints. Independent cause of death review may provide more consistent definitions of lung cancer related death than death certificates. Reference Horeweg Nanda, et al. ‘Blinded and uniform cause of death verification in a lung cancer CT screening trial.’ Lung Cancer 2012;77(3):522–525.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.140 | 0.158 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".